#!/bin/sh
#
# 简单写一下脚本的功能。
#
#
#

if [ $# -ne 1 ]; then
	echo "Usage: $0 mdfile"
	exit
fi

awk -F '[（）]' '{

	if (NF>1) {
		for (counter = 2; counter < NF+1; counter =counter+2) {

			print "（" $counter "）"
		}
	} 
}'  $1 | sort |uniq 
